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Method for preparing polyoxymethylene dimethyl ether catalyzed by molecular sieve with high silicon-aluminum ratio

A polyoxymethylene dimethyl ether, a catalytic preparation technology, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of many by-products, increase the pressure, increase the complexity of the reaction, etc., to achieve easy and liquid Effects of phase separation, high reusability, and excellent settling performance

Active Publication Date: 2016-01-27
SHANXI INST OF COAL CHEM CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The use of methanol as a raw material will lead to the formation of hemiacetal in the product, which will lead to the decline of the performance of the target product
Paraformaldehyde is cheap and replaces paraformaldehyde in traditional raw materials, reducing the cost of raw materials to a certain extent, but using paraformaldehyde as a raw material will reduce the selectivity of the target product and cause many by-products
At the same time, part of the reaction process increases the pressure and increases the complexity of the reaction.
Moreover, this invention only introduces the catalytic performance of some low-silicon-aluminum ratio molecular sieves, and does not fully describe the detailed effect of hydrogen-type molecular sieves on this reaction.

Method used

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  • Method for preparing polyoxymethylene dimethyl ether catalyzed by molecular sieve with high silicon-aluminum ratio

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Select 5gNaZSM-48 (Si / Al=220) molecular sieves and place them in a round bottom flask, then add 150ml of deionized water, 8g of ammonium chloride, and heat to 80 in a water bath o C and constantly stirring for 4h, centrifugal filtration, after obtaining the molecular sieve filter cake, repeat the above steps once. Finally, the gained molecular sieve 110 o C drying 12h, grinding, 550 o C roasting 10h, obtains hydrogen type molecular sieve;

[0027] Add 0.83g of catalyst HZSM-48 (Si / Al=220), 7.6g of methylal and 9.0g of paraformaldehyde into a 100ml tank reactor, heat to 120°C and stir for 0.75h, centrifuge to separate the catalyst and reaction product, collect Liquid phase product, add internal standard and carry out gas chromatographic analysis, comprise unreacted methylal and paraformaldehyde in the product, product composition distribution is as follows (expressed in % by weight): methylal 16.8%, paraformaldehyde 3.9%, Methyl formate 3.2%, PODE 2-8 = 75.2%.

Embodiment 2

[0029] Select 5gNaZSM-48 (Si / Al=380) molecular sieves and place them in a round bottom flask, then add 150ml of deionized water, 24g of ammonium nitrate, and heat to 70 in a water bath o C and constantly stirring for 5h, centrifugal filtration, after obtaining the molecular sieve filter cake, repeat the above steps once. Finally, the gained molecular sieve 110 o C drying 12h, grinding, 550 o C roasting 10h, obtains hydrogen type molecular sieve;

[0030] Add 0.5g of catalyst HZSM-48 (Si / Al=380), 38g of methylal and 9.0g of paraformaldehyde into a 100ml tank reactor, heat to 140°C and stir for 6h, centrifuge to separate the catalyst and reaction product, and collect the liquid phase Product, add internal standard and carry out gas chromatographic analysis, comprise unreacted methylal and paraformaldehyde in the product, product composition distribution is as follows (expressed with weight %): methylal 30.2%, paraformaldehyde 0.0%, formic acid formaldehyde Ester 3.2%, PODE 2...

Embodiment 3

[0032] Select 10g NaMCM-41 (Si / Al=400) molecular sieves and place them in a round bottom flask, then add 300ml of deionized water, 16g of ammonium chloride, and heat to 80 in a water bath o C and constantly stirring for 4h, centrifugal filtration, after obtaining the molecular sieve filter cake, repeat the above steps once. Finally, the gained molecular sieve 110 o C drying 12h, grinding, 550 o C roasting 10h, obtains hydrogen type molecular sieve;

[0033] Add 0.7g of catalyst HMCM-41 (Si / Al=400), 15.2g of methylal and 9.0g of paraformaldehyde into a 100ml tank reactor, heat to 160°C and stir for 4h, centrifuge to separate the catalyst and reaction product, and collect the liquid Phase product, add internal standard and carry out gas chromatographic analysis, comprise unreacted methylal and paraformaldehyde in the product, product composition distribution is as follows (expressed by weight %): methylal 20.9%, paraformaldehyde 3.8%, formic acid Methyl ester 1.5%, PODE 2-8 ...

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Abstract

A method for preparing polyoxymethylene dimethyl ether under the catalysis of a molecular sieve with a high silica-alumina ratio is characterized in that raw materials comprising methylal and trioxymethylene undergo a contact reaction at a reaction temperature of 60-200DEG C under stirring under the catalysis of a hydrogen molecular sieve catalyst for 0.2-48h to generate polyoxymethylene dimethyl ether, and the catalyst and the obtained liquid product are separated through centrifuge after the reaction, wherein a molar ratio of methylal to trioxymethylene is 1-5, and the amount of the catalyst is 1-10wt% of the amount of the above total reactants. The method has the advantages of simple separation, low energy consumption, no corrosion, high selectivity of the target product, and high reuse rate of the catalyst.

Description

technical field [0001] The invention belongs to a method for preparing polyoxymethylene dimethyl ether, in particular to a method for preparing polyoxymethylene dimethyl ether with a high-silicon-aluminum ratio molecular sieve as an efficient catalyst. Background technique [0002] Polyoxymethylene dimethyl ether (PODE n ) is a general term for a class of polyether substances, the chemical formula is CH 3 (CH 2 O) n OCH 3 , (n>1), the oligomer is a colorless, clear, flammable liquid with a pungent odor. PODE n With high oxygen content (42%-51%) and cetane number (>60), especially PODE 2-8 , due to its very similar physical properties to diesel, adding an appropriate amount of diesel can improve the combustion of diesel in the engine, improve thermal efficiency, and greatly reduce the emissions of nitrogen oxides and carbon monoxide in the exhaust, and PODE 2-8 As a diesel additive, there is no need to make any changes to the existing engine equipment, and it is ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C43/30C07C41/56
CPCC07C41/56C07C43/30
Inventor 王建国武建兵吴志伟朱华青秦张峰樊卫斌
Owner SHANXI INST OF COAL CHEM CHINESE ACAD OF SCI